Foul exhaust troubling on new car

Dear Doctor: My 2018 Buick Encore with the turbocharged engine has an ugly odor, as if exhaust fumes are entering the cabin. The technician followed the trouble flow chart for P0420 and found a faulty catalytic converter and failed upstream oxygen sensor, and he replaced the cat and gaskets. Two months later I returned to the dealer with the same smelly issue and he found coolant leaking from the turbocharger and coolant feed pipe line; he replaced the turbocharger, coolant feed pipe, and cat converter clap. One month later, the odor is getting worse, and the technician found a leak in the turbo coolant feed pipe, and replaced it. I still have the problem. What should I do next?

– Argyle

Dear Argyle: A smell out the exhaust is the result of the catalytic converter trying to clean the exhaust. Let’s talk about the catalytic converter code. This code indicates poor catalytic converter performance. On a brand new car such as your 2018 Buick something has to be causing the catalytic converter not to perform. A failing upstream 02 sensor indication on this car with the catalytic converter fault indicates an engine fault.

Dear Doctor: I want to buy a new truck to keep for more than 10 years. My current 2007 Ford F-150 has low miles but is kept outside and is rusting like crazy. Should I buy the new aluminum F-150 so it doesn’t rust, or go with a new Toyota Tacoma for the reliability? I like the F-150, and if it will last longer than the Toyota, that would be my choice.

– Mark

Dear Mark: Any vehicle will rust over time. Some trucks will rust sooner than others due to harsh salt and road chemicals. Both are great trucks, however they’re both completely different in every way. The Toyota is more compact, and rides more like a truck and higher off the ground. The F-150 is larger, lower, and gives a more car-like ride. The F-150 may also have better gas mileage. You should buy the truck you like best and don’t worry about the rusting.

Dear Doctor: I had a dealer-service oil change on my 2013 Lexus RX 350. The service adviser told me it’s also time to change the brake fluid. My vehicle has only 21,000 miles, but he said it should be done every three years, regardless of mileage. Did I waste my money having this service performed?

– Herb

Dear Herb: Your car is very low in mileage and only five years old. At this point I disagree with the service adviser. The recommendations are done in multi-color check box suggestions red, yellow, and green. The recommended services in some cases cost more than the car is worth. I’m all for the service adviser suggesting services, but not big overselling.

Dear Doctor: I have a 2018 Chevy Silverado. What modifications can I make to the engine and chassis without running into problems with voiding warranties? I don’t want to do something and have General Motors say it was my fault for changing or adding something.

– Joel

Dear Joel: I’ve done a lot of bolt-on items. The one area of most concern is changing the exhaust to dual tailpipes. Usually the replacement muffler is smaller and much louder than the stock system with no advantage except noise. Other options include a fresh-air intake (cold-air intake) system and a computer download re-tune. For best performance, it may require premium gasoline. Be advised I would download the stock (original) tune to the ECM (computer) before going in for service. Your Silverado is a great truck with lots of power and comfort.

Dear Doctor: The Toyota Yaris has been around for while and I’m considering downsizing to a small car, so since it’s been around for a while, I’m wondering if you have any opinions on it.

– Alan

Dear Alan: The Toyota Yaris was not one of my favorite cars a few years ago, but I find the 2018 Yaris to be a solid Toyota product. The Yaris has grown up and now I consider it a good compact car. It comes with either a manual transmission or four-speed automatic. I drove the automatic version. The fuel economy fell short of my expectations of 32-33 mpg. I think gas mileage would be better if equipped with a five-speed automatic. The Yaris is easy to drive and park, with good visibility from all windows. There are many options when it comes to vehicle selection, so take your time on a road test and mark all the pros and cons.

Junior Damato is an ASE-certified Master Technician.

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